Add -Wmissing-exported-pattern-synonym-signatures

After !4741, it was no longer possible to silence a warning about a missing
pattern synonym signature if the `-Wmissing-signatures` flag was on.

Restore the previous semantics while still adhering to the principle "enabling
an additional warning flag should never make prior warnings disappear".

For more symmetry and granularity, introduce
`-Wmissing-exported-pattern-synonym-signatures`.

See Note [Missing signatures] for an overview of all flags involved.

19 files changed, 255 insertions, 352 deletions

diff --git a/compiler/GHC/Driver/Flags.hs b/compiler/GHC/Driver/Flags.hs
index 97039cbcf8..19f730ed19 100644
--- a/compiler/GHC/Driver/Flags.hs
+++ b/compiler/GHC/Driver/Flags.hs
@@ -534,6 +534,7 @@ data WarningFlag =
    | Opt_WarnAmbiguousFields                -- Since 9.2
    | Opt_WarnImplicitLift                 -- Since 9.2
    | Opt_WarnMissingKindSignatures        -- Since 9.2
+   | Opt_WarnMissingExportedPatternSynonymSignatures -- since 9.2
    deriving (Eq, Show, Enum)
 
 -- | Return the names of a WarningFlag
@@ -542,95 +543,96 @@ data WarningFlag =
 -- the "preferred one" that will be displayed in warning messages.
 warnFlagNames :: WarningFlag -> NonEmpty String
 warnFlagNames wflag = case wflag of
-  Opt_WarnAlternativeLayoutRuleTransitional -> "alternative-layout-rule-transitional" :| []
-  Opt_WarnAmbiguousFields                   -> "ambiguous-fields" :| []
-  Opt_WarnAutoOrphans                       -> "auto-orphans" :| []
-  Opt_WarnCPPUndef                          -> "cpp-undef" :| []
-  Opt_WarnUnbangedStrictPatterns            -> "unbanged-strict-patterns" :| []
-  Opt_WarnDeferredTypeErrors                -> "deferred-type-errors" :| []
-  Opt_WarnDeferredOutOfScopeVariables       -> "deferred-out-of-scope-variables" :| []
-  Opt_WarnWarningsDeprecations              -> "deprecations" :| ["warnings-deprecations"]
-  Opt_WarnDeprecatedFlags                   -> "deprecated-flags" :| []
-  Opt_WarnDerivingDefaults                  -> "deriving-defaults" :| []
-  Opt_WarnDerivingTypeable                  -> "deriving-typeable" :| []
-  Opt_WarnDodgyExports                      -> "dodgy-exports" :| []
-  Opt_WarnDodgyForeignImports               -> "dodgy-foreign-imports" :| []
-  Opt_WarnDodgyImports                      -> "dodgy-imports" :| []
-  Opt_WarnEmptyEnumerations                 -> "empty-enumerations" :| []
-  Opt_WarnDuplicateConstraints              -> "duplicate-constraints" :| []
-  Opt_WarnRedundantConstraints              -> "redundant-constraints" :| []
-  Opt_WarnDuplicateExports                  -> "duplicate-exports" :| []
-  Opt_WarnHiShadows                         -> "hi-shadowing" :| []
-  Opt_WarnInaccessibleCode                  -> "inaccessible-code" :| []
-  Opt_WarnImplicitPrelude                   -> "implicit-prelude" :| []
-  Opt_WarnImplicitKindVars                  -> "implicit-kind-vars" :| []
-  Opt_WarnIncompletePatterns                -> "incomplete-patterns" :| []
-  Opt_WarnIncompletePatternsRecUpd          -> "incomplete-record-updates" :| []
-  Opt_WarnIncompleteUniPatterns             -> "incomplete-uni-patterns" :| []
-  Opt_WarnInlineRuleShadowing               -> "inline-rule-shadowing" :| []
-  Opt_WarnIdentities                        -> "identities" :| []
-  Opt_WarnMissingFields                     -> "missing-fields" :| []
-  Opt_WarnMissingImportList                 -> "missing-import-lists" :| []
-  Opt_WarnMissingExportList                 -> "missing-export-lists" :| []
-  Opt_WarnMissingLocalSignatures            -> "missing-local-signatures" :| []
-  Opt_WarnMissingMethods                    -> "missing-methods" :| []
-  Opt_WarnMissingMonadFailInstances         -> "missing-monadfail-instances" :| []
-  Opt_WarnSemigroup                         -> "semigroup" :| []
-  Opt_WarnMissingSignatures                 -> "missing-signatures" :| []
-  Opt_WarnMissingKindSignatures             -> "missing-kind-signatures" :| []
-  Opt_WarnMissingExportedSignatures         -> "missing-exported-signatures" :| []
-  Opt_WarnMonomorphism                      -> "monomorphism-restriction" :| []
-  Opt_WarnNameShadowing                     -> "name-shadowing" :| []
-  Opt_WarnNonCanonicalMonadInstances        -> "noncanonical-monad-instances" :| []
-  Opt_WarnNonCanonicalMonadFailInstances    -> "noncanonical-monadfail-instances" :| []
-  Opt_WarnNonCanonicalMonoidInstances       -> "noncanonical-monoid-instances" :| []
-  Opt_WarnOrphans                           -> "orphans" :| []
-  Opt_WarnOverflowedLiterals                -> "overflowed-literals" :| []
-  Opt_WarnOverlappingPatterns               -> "overlapping-patterns" :| []
-  Opt_WarnMissedSpecs                       -> "missed-specialisations" :| ["missed-specializations"]
-  Opt_WarnAllMissedSpecs                    -> "all-missed-specialisations" :| ["all-missed-specializations"]
-  Opt_WarnSafe                              -> "safe" :| []
-  Opt_WarnTrustworthySafe                   -> "trustworthy-safe" :| []
-  Opt_WarnInferredSafeImports               -> "inferred-safe-imports" :| []
-  Opt_WarnMissingSafeHaskellMode            -> "missing-safe-haskell-mode" :| []
-  Opt_WarnTabs                              -> "tabs" :| []
-  Opt_WarnTypeDefaults                      -> "type-defaults" :| []
-  Opt_WarnTypedHoles                        -> "typed-holes" :| []
-  Opt_WarnPartialTypeSignatures             -> "partial-type-signatures" :| []
-  Opt_WarnUnrecognisedPragmas               -> "unrecognised-pragmas" :| []
-  Opt_WarnUnsafe                            -> "unsafe" :| []
-  Opt_WarnUnsupportedCallingConventions     -> "unsupported-calling-conventions" :| []
-  Opt_WarnUnsupportedLlvmVersion            -> "unsupported-llvm-version" :| []
-  Opt_WarnMissedExtraSharedLib              -> "missed-extra-shared-lib" :| []
-  Opt_WarnUntickedPromotedConstructors      -> "unticked-promoted-constructors" :| []
-  Opt_WarnUnusedDoBind                      -> "unused-do-bind" :| []
-  Opt_WarnUnusedForalls                     -> "unused-foralls" :| []
-  Opt_WarnUnusedImports                     -> "unused-imports" :| []
-  Opt_WarnUnusedLocalBinds                  -> "unused-local-binds" :| []
-  Opt_WarnUnusedMatches                     -> "unused-matches" :| []
-  Opt_WarnUnusedPatternBinds                -> "unused-pattern-binds" :| []
-  Opt_WarnUnusedTopBinds                    -> "unused-top-binds" :| []
-  Opt_WarnUnusedTypePatterns                -> "unused-type-patterns" :| []
-  Opt_WarnUnusedRecordWildcards             -> "unused-record-wildcards" :| []
-  Opt_WarnRedundantBangPatterns             -> "redundant-bang-patterns" :| []
-  Opt_WarnRedundantRecordWildcards          -> "redundant-record-wildcards" :| []
-  Opt_WarnWrongDoBind                       -> "wrong-do-bind" :| []
-  Opt_WarnMissingPatternSynonymSignatures   -> "missing-pattern-synonym-signatures" :| []
-  Opt_WarnMissingDerivingStrategies         -> "missing-deriving-strategies" :| []
-  Opt_WarnSimplifiableClassConstraints      -> "simplifiable-class-constraints" :| []
-  Opt_WarnMissingHomeModules                -> "missing-home-modules" :| []
-  Opt_WarnUnrecognisedWarningFlags          -> "unrecognised-warning-flags" :| []
-  Opt_WarnStarBinder                        -> "star-binder" :| []
-  Opt_WarnStarIsType                        -> "star-is-type" :| []
-  Opt_WarnSpaceAfterBang                    -> "missing-space-after-bang" :| []
-  Opt_WarnPartialFields                     -> "partial-fields" :| []
-  Opt_WarnPrepositiveQualifiedModule        -> "prepositive-qualified-module" :| []
-  Opt_WarnUnusedPackages                    -> "unused-packages" :| []
-  Opt_WarnCompatUnqualifiedImports          -> "compat-unqualified-imports" :| []
-  Opt_WarnInvalidHaddock                    -> "invalid-haddock" :| []
-  Opt_WarnOperatorWhitespaceExtConflict     -> "operator-whitespace-ext-conflict" :| []
-  Opt_WarnOperatorWhitespace                -> "operator-whitespace" :| []
-  Opt_WarnImplicitLift                      -> "implicit-lift" :| []
+  Opt_WarnAlternativeLayoutRuleTransitional       -> "alternative-layout-rule-transitional" :| []
+  Opt_WarnAmbiguousFields                         -> "ambiguous-fields" :| []
+  Opt_WarnAutoOrphans                             -> "auto-orphans" :| []
+  Opt_WarnCPPUndef                                -> "cpp-undef" :| []
+  Opt_WarnUnbangedStrictPatterns                  -> "unbanged-strict-patterns" :| []
+  Opt_WarnDeferredTypeErrors                      -> "deferred-type-errors" :| []
+  Opt_WarnDeferredOutOfScopeVariables             -> "deferred-out-of-scope-variables" :| []
+  Opt_WarnWarningsDeprecations                    -> "deprecations" :| ["warnings-deprecations"]
+  Opt_WarnDeprecatedFlags                         -> "deprecated-flags" :| []
+  Opt_WarnDerivingDefaults                        -> "deriving-defaults" :| []
+  Opt_WarnDerivingTypeable                        -> "deriving-typeable" :| []
+  Opt_WarnDodgyExports                            -> "dodgy-exports" :| []
+  Opt_WarnDodgyForeignImports                     -> "dodgy-foreign-imports" :| []
+  Opt_WarnDodgyImports                            -> "dodgy-imports" :| []
+  Opt_WarnEmptyEnumerations                       -> "empty-enumerations" :| []
+  Opt_WarnDuplicateConstraints                    -> "duplicate-constraints" :| []
+  Opt_WarnRedundantConstraints                    -> "redundant-constraints" :| []
+  Opt_WarnDuplicateExports                        -> "duplicate-exports" :| []
+  Opt_WarnHiShadows                               -> "hi-shadowing" :| []
+  Opt_WarnInaccessibleCode                        -> "inaccessible-code" :| []
+  Opt_WarnImplicitPrelude                         -> "implicit-prelude" :| []
+  Opt_WarnImplicitKindVars                        -> "implicit-kind-vars" :| []
+  Opt_WarnIncompletePatterns                      -> "incomplete-patterns" :| []
+  Opt_WarnIncompletePatternsRecUpd                -> "incomplete-record-updates" :| []
+  Opt_WarnIncompleteUniPatterns                   -> "incomplete-uni-patterns" :| []
+  Opt_WarnInlineRuleShadowing                     -> "inline-rule-shadowing" :| []
+  Opt_WarnIdentities                              -> "identities" :| []
+  Opt_WarnMissingFields                           -> "missing-fields" :| []
+  Opt_WarnMissingImportList                       -> "missing-import-lists" :| []
+  Opt_WarnMissingExportList                       -> "missing-export-lists" :| []
+  Opt_WarnMissingLocalSignatures                  -> "missing-local-signatures" :| []
+  Opt_WarnMissingMethods                          -> "missing-methods" :| []
+  Opt_WarnMissingMonadFailInstances               -> "missing-monadfail-instances" :| []
+  Opt_WarnSemigroup                               -> "semigroup" :| []
+  Opt_WarnMissingSignatures                       -> "missing-signatures" :| []
+  Opt_WarnMissingKindSignatures                   -> "missing-kind-signatures" :| []
+  Opt_WarnMissingExportedSignatures               -> "missing-exported-signatures" :| []
+  Opt_WarnMonomorphism                            -> "monomorphism-restriction" :| []
+  Opt_WarnNameShadowing                           -> "name-shadowing" :| []
+  Opt_WarnNonCanonicalMonadInstances              -> "noncanonical-monad-instances" :| []
+  Opt_WarnNonCanonicalMonadFailInstances          -> "noncanonical-monadfail-instances" :| []
+  Opt_WarnNonCanonicalMonoidInstances             -> "noncanonical-monoid-instances" :| []
+  Opt_WarnOrphans                                 -> "orphans" :| []
+  Opt_WarnOverflowedLiterals                      -> "overflowed-literals" :| []
+  Opt_WarnOverlappingPatterns                     -> "overlapping-patterns" :| []
+  Opt_WarnMissedSpecs                             -> "missed-specialisations" :| ["missed-specializations"]
+  Opt_WarnAllMissedSpecs                          -> "all-missed-specialisations" :| ["all-missed-specializations"]
+  Opt_WarnSafe                                    -> "safe" :| []
+  Opt_WarnTrustworthySafe                         -> "trustworthy-safe" :| []
+  Opt_WarnInferredSafeImports                     -> "inferred-safe-imports" :| []
+  Opt_WarnMissingSafeHaskellMode                  -> "missing-safe-haskell-mode" :| []
+  Opt_WarnTabs                                    -> "tabs" :| []
+  Opt_WarnTypeDefaults                            -> "type-defaults" :| []
+  Opt_WarnTypedHoles                              -> "typed-holes" :| []
+  Opt_WarnPartialTypeSignatures                   -> "partial-type-signatures" :| []
+  Opt_WarnUnrecognisedPragmas                     -> "unrecognised-pragmas" :| []
+  Opt_WarnUnsafe                                  -> "unsafe" :| []
+  Opt_WarnUnsupportedCallingConventions           -> "unsupported-calling-conventions" :| []
+  Opt_WarnUnsupportedLlvmVersion                  -> "unsupported-llvm-version" :| []
+  Opt_WarnMissedExtraSharedLib                    -> "missed-extra-shared-lib" :| []
+  Opt_WarnUntickedPromotedConstructors            -> "unticked-promoted-constructors" :| []
+  Opt_WarnUnusedDoBind                            -> "unused-do-bind" :| []
+  Opt_WarnUnusedForalls                           -> "unused-foralls" :| []
+  Opt_WarnUnusedImports                           -> "unused-imports" :| []
+  Opt_WarnUnusedLocalBinds                        -> "unused-local-binds" :| []
+  Opt_WarnUnusedMatches                           -> "unused-matches" :| []
+  Opt_WarnUnusedPatternBinds                      -> "unused-pattern-binds" :| []
+  Opt_WarnUnusedTopBinds                          -> "unused-top-binds" :| []
+  Opt_WarnUnusedTypePatterns                      -> "unused-type-patterns" :| []
+  Opt_WarnUnusedRecordWildcards                   -> "unused-record-wildcards" :| []
+  Opt_WarnRedundantBangPatterns                   -> "redundant-bang-patterns" :| []
+  Opt_WarnRedundantRecordWildcards                -> "redundant-record-wildcards" :| []
+  Opt_WarnWrongDoBind                             -> "wrong-do-bind" :| []
+  Opt_WarnMissingPatternSynonymSignatures         -> "missing-pattern-synonym-signatures" :| []
+  Opt_WarnMissingDerivingStrategies               -> "missing-deriving-strategies" :| []
+  Opt_WarnSimplifiableClassConstraints            -> "simplifiable-class-constraints" :| []
+  Opt_WarnMissingHomeModules                      -> "missing-home-modules" :| []
+  Opt_WarnUnrecognisedWarningFlags                -> "unrecognised-warning-flags" :| []
+  Opt_WarnStarBinder                              -> "star-binder" :| []
+  Opt_WarnStarIsType                              -> "star-is-type" :| []
+  Opt_WarnSpaceAfterBang                          -> "missing-space-after-bang" :| []
+  Opt_WarnPartialFields                           -> "partial-fields" :| []
+  Opt_WarnPrepositiveQualifiedModule              -> "prepositive-qualified-module" :| []
+  Opt_WarnUnusedPackages                          -> "unused-packages" :| []
+  Opt_WarnCompatUnqualifiedImports                -> "compat-unqualified-imports" :| []
+  Opt_WarnInvalidHaddock                          -> "invalid-haddock" :| []
+  Opt_WarnOperatorWhitespaceExtConflict           -> "operator-whitespace-ext-conflict" :| []
+  Opt_WarnOperatorWhitespace                      -> "operator-whitespace" :| []
+  Opt_WarnImplicitLift                            -> "implicit-lift" :| []
+  Opt_WarnMissingExportedPatternSynonymSignatures -> "missing-exported-pattern-synonym-signatures" :| []
 
 -- -----------------------------------------------------------------------------
 -- Standard sets of warning options
diff --git a/compiler/GHC/Driver/Session.hs b/compiler/GHC/Driver/Session.hs
index 4e570f1b3e..f6095677e4 100644
--- a/compiler/GHC/Driver/Session.hs
+++ b/compiler/GHC/Driver/Session.hs
@@ -3243,7 +3243,8 @@ wWarningFlagsDeps = mconcat [
   warnSpec    Opt_WarnInvalidHaddock,
   warnSpec    Opt_WarnOperatorWhitespaceExtConflict,
   warnSpec    Opt_WarnOperatorWhitespace,
-  warnSpec    Opt_WarnImplicitLift
+  warnSpec    Opt_WarnImplicitLift,
+  warnSpec    Opt_WarnMissingExportedPatternSynonymSignatures
  ]
 
 -- | These @-\<blah\>@ flags can all be reversed with @-no-\<blah\>@
diff --git a/compiler/GHC/Rename/Names.hs b/compiler/GHC/Rename/Names.hs
index ee545b9132..fa19bdc600 100644
--- a/compiler/GHC/Rename/Names.hs
+++ b/compiler/GHC/Rename/Names.hs
@@ -1482,6 +1482,28 @@ reportUnusedNames gbl_env hsc_src
 *                                                                      *
 ********************************************************************* -}
 
+{-
+Note [Missing signatures]
+~~~~~~~~~~~~~~~~~~~~~~~~~
+There are four warning flags in play:
+
+  * -Wmissing-exported-signatures
+    Warn about any exported top-level function/value without a type signature.
+    Does not include pattern synonyms.
+
+  * -Wmissing-signatures
+    Warn about any top-level function/value without a type signature. Does not
+    include pattern synonyms. Takes priority over -Wmissing-exported-signatures.
+
+  * -Wmissing-exported-pattern-synonym-signatures
+    Warn about any exported pattern synonym without a type signature.
+
+  * -Wmissing-pattern-synonym-signatures
+    Warn about any pattern synonym without a type signature. Takes priority over
+    -Wmissing-exported-pattern-synonym-signatures.
+
+-}
+
 -- | Warn the user about top level binders that lack type signatures.
 -- Called /after/ type inference, so that we can report the
 -- inferred type of the function
@@ -1495,46 +1517,56 @@ warnMissingSignatures gbl_env
 
          -- Warn about missing signatures
          -- Do this only when we have a type to offer
-       ; warn_missing_sigs  <- woptM Opt_WarnMissingSignatures
-       ; warn_only_exported <- woptM Opt_WarnMissingExportedSignatures
-       ; warn_pat_syns      <- woptM Opt_WarnMissingPatternSynonymSignatures
+       ; warn_binds             <- woptM Opt_WarnMissingSignatures
+       ; warn_exported_binds    <- woptM Opt_WarnMissingExportedSignatures
+       ; warn_pat_syns          <- woptM Opt_WarnMissingPatternSynonymSignatures
+       ; warn_exported_pat_syns <- woptM Opt_WarnMissingExportedPatternSynonymSignatures
 
+         -- See Note [Missing signatures]
        ; let add_sig_warns
-               | warn_missing_sigs  = add_warns Opt_WarnMissingSignatures
-               | warn_only_exported = add_warns Opt_WarnMissingExportedSignatures
-               | warn_pat_syns      = add_warns Opt_WarnMissingPatternSynonymSignatures
-               | otherwise          = return ()
-
-             add_warns flag
-                = when (warn_missing_sigs || warn_only_exported)
-                       (mapM_ add_bind_warn binds) >>
-                  when (warn_missing_sigs || warn_pat_syns)
-                       (mapM_ add_pat_syn_warn pat_syns)
-                where
-                  add_pat_syn_warn p
-                    = add_warn name $
-                      hang (text "Pattern synonym with no type signature:")
-                         2 (text "pattern" <+> pprPrefixName name <+> dcolon <+> pp_ty)
-                    where
-                      name  = patSynName p
-                      pp_ty = pprPatSynType p
-
-                  add_bind_warn :: Id -> IOEnv (Env TcGblEnv TcLclEnv) ()
-                  add_bind_warn id
-                    = do { env <- tcInitTidyEnv     -- Why not use emptyTidyEnv?
-                         ; let name    = idName id
-                               (_, ty) = tidyOpenType env (idType id)
-                               ty_msg  = pprSigmaType ty
-                         ; add_warn name $
-                           hang (text "Top-level binding with no type signature:")
-                              2 (pprPrefixName name <+> dcolon <+> ty_msg) }
-
-                  add_warn name msg
-                    = when (name `elemNameSet` sig_ns && export_check name)
-                           (addDiagnosticAt (WarningWithFlag flag) (getSrcSpan name) msg)
-
-                  export_check name
-                    = warn_missing_sigs || not warn_only_exported || name `elemNameSet` exports
+               = when (warn_pat_syns || warn_exported_pat_syns)
+                      (mapM_ add_pat_syn_warn pat_syns) >>
+                 when (warn_binds || warn_exported_binds)
+                      (mapM_ add_bind_warn binds)
+
+             add_pat_syn_warn p
+               = when export_check $
+                 add_warn name flag $
+                 hang (text "Pattern synonym with no type signature:")
+                    2 (text "pattern" <+> pprPrefixName name <+> dcolon <+> pp_ty)
+               where
+                 name  = patSynName p
+                 pp_ty = pprPatSynType p
+                 export_check = warn_pat_syns || name `elemNameSet` exports
+                 flag | warn_pat_syns
+                      = Opt_WarnMissingPatternSynonymSignatures
+                      | otherwise
+                      = Opt_WarnMissingExportedPatternSynonymSignatures
+
+             add_bind_warn :: Id -> IOEnv (Env TcGblEnv TcLclEnv) ()
+             add_bind_warn id
+               = do { env <- tcInitTidyEnv     -- Why not use emptyTidyEnv?
+                    ; let (_, ty) = tidyOpenType env (idType id)
+                          ty_msg  = pprSigmaType ty
+
+                    ; when export_check $
+                      add_warn name flag $
+                      hang (text "Top-level binding with no type signature:")
+                         2 (pprPrefixName name <+> dcolon <+> ty_msg) }
+               where
+                 name = idName id
+                 export_check = warn_binds || name `elemNameSet` exports
+                 flag | warn_binds
+                      = Opt_WarnMissingSignatures
+                      | otherwise
+                      = Opt_WarnMissingExportedSignatures
+
+             add_warn name flag msg
+               = when not_ghc_generated
+                      (addDiagnosticAt (WarningWithFlag flag) (getSrcSpan name) msg)
+               where
+                 not_ghc_generated
+                   = name `elemNameSet` sig_ns
 
        ; add_sig_warns }
 
diff --git a/docs/users_guide/using-warnings.rst b/docs/users_guide/using-warnings.rst
index f34d4c7ca2..dc21cd468f 100644
--- a/docs/users_guide/using-warnings.rst
+++ b/docs/users_guide/using-warnings.rst
@@ -1204,6 +1204,24 @@ of ``-W(no-)*``.
 
     This option is off by default.
 
+.. ghc-flag:: -Wmissing-exported-pattern-synonym-signatures
+    :shortdesc: warn about pattern synonyms without signatures, only if they
+        are exported
+    :type: dynamic
+    :reverse: -Wno-missing-exported-pattern-synonym-signatures
+    :category:
+
+    .. index::
+       single: type signatures, missing, pattern synonyms
+
+    If you would like GHC to check that every exported pattern synonym has a
+    type signature, but not check unexported pattern synonyms, use the
+    :ghc-flag:`-Wmissing-exported-pattern-synonym-signatures` option. If this
+    option is used in conjunction with
+    :ghc-flag:`-Wmissing-pattern-synonym-signatures` then every pattern synonym
+    must have a type signature. As part of the warning GHC also reports the
+    inferred type. The option is off by default.
+
 .. ghc-flag:: -Wname-shadowing
     :shortdesc: warn when names are shadowed
     :type: dynamic
diff --git a/testsuite/tests/warnings/should_compile/T14794a.hs b/testsuite/tests/warnings/should_compile/T14794a.hs
index 224eaf64f7..216ef832b3 100644
--- a/testsuite/tests/warnings/should_compile/T14794a.hs
+++ b/testsuite/tests/warnings/should_compile/T14794a.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-signatures -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures #-}
+{-# OPTIONS_GHC -Wmissing-signatures #-}
 
-module T14794a (test1, pattern Test2, test3, pattern Test4) where
+module T14794a (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-signatures -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures
+-- These should generate warnings:
 
-test3 = True
+testExported = True
 
-pattern Test4 <- True
+testUnexported = True
 
-test7 = True
+-- These should not generate warnings:
 
-pattern Test8 <- True
+pattern TestExported <- True
 
-
--- This should not generate warnings with;
--- -Wmissing-signatures -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
+pattern TestUnexported <- True
diff --git a/testsuite/tests/warnings/should_compile/T14794a.stderr b/testsuite/tests/warnings/should_compile/T14794a.stderr
index 166d59ab37..807a070350 100644
--- a/testsuite/tests/warnings/should_compile/T14794a.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794a.stderr
@@ -1,12 +1,6 @@
 
-T14794a.hs:9:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test3 :: Bool
+T14794a.hs:8:1: warning: [-Wmissing-signatures (in -Wall)]
+    Top-level binding with no type signature: testExported :: Bool
 
-T14794a.hs:11:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794a.hs:13:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test7 :: Bool
-
-T14794a.hs:15:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
+T14794a.hs:10:1: warning: [-Wmissing-signatures (in -Wall)]
+    Top-level binding with no type signature: testUnexported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794b.hs b/testsuite/tests/warnings/should_compile/T14794b.hs
index 7c542b4dc1..90501d0fa7 100644
--- a/testsuite/tests/warnings/should_compile/T14794b.hs
+++ b/testsuite/tests/warnings/should_compile/T14794b.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-signatures -Wmissing-exported-signatures #-}
+{-# OPTIONS_GHC -Wmissing-exported-signatures #-}
 
-module T14794b (test1, pattern Test2, test3, pattern Test4) where
+module T14794b (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-signatures -Wmissing-exported-signatures
+-- These should generate warnings:
 
-test3 = True
+testExported = True
 
-pattern Test4 <- True
+-- These should not generate warnings:
 
-test7 = True
+testUnexported = True
 
-pattern Test8 <- True
+pattern TestExported <- True
 
-
--- This should not generate warnings with;
--- -Wmissing-signatures -Wmissing-exported-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
+pattern TestUnexported <- True
diff --git a/testsuite/tests/warnings/should_compile/T14794b.stderr b/testsuite/tests/warnings/should_compile/T14794b.stderr
index 6109a4c985..8f7f7e805b 100644
--- a/testsuite/tests/warnings/should_compile/T14794b.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794b.stderr
@@ -1,12 +1,3 @@
 
-T14794b.hs:9:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test3 :: Bool
-
-T14794b.hs:11:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794b.hs:13:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test7 :: Bool
-
-T14794b.hs:15:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
+T14794b.hs:8:1: warning: [-Wmissing-exported-signatures]
+    Top-level binding with no type signature: testExported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794c.hs b/testsuite/tests/warnings/should_compile/T14794c.hs
index 742ca3c91c..fd30cfdfcd 100644
--- a/testsuite/tests/warnings/should_compile/T14794c.hs
+++ b/testsuite/tests/warnings/should_compile/T14794c.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-signatures -Wmissing-pattern-synonym-signatures #-}
+{-# OPTIONS_GHC -Wmissing-signatures -Wmissing-exported-signatures #-}
 
-module T14794c (test1, pattern Test2, test3, pattern Test4) where
+module T14794c (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-signatures -Wmissing-pattern-synonym-signatures
+-- These should generate warnings:
 
-test3 = True
+testExported = True
 
-pattern Test4 <- True
+testUnexported = True
 
-test7 = True
+-- These should not generate warnings:
 
-pattern Test8 <- True
+pattern TestExported <- True
 
-
--- This should not generate warnings with;
--- -Wmissing-signatures -Wmissing-pattern-synonym-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
+pattern TestUnexported <- True
diff --git a/testsuite/tests/warnings/should_compile/T14794c.stderr b/testsuite/tests/warnings/should_compile/T14794c.stderr
index 95cbb4d16f..413eea960f 100644
--- a/testsuite/tests/warnings/should_compile/T14794c.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794c.stderr
@@ -1,12 +1,6 @@
 
-T14794c.hs:9:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test3 :: Bool
+T14794c.hs:8:1: warning: [-Wmissing-signatures (in -Wall)]
+    Top-level binding with no type signature: testExported :: Bool
 
-T14794c.hs:11:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794c.hs:13:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test7 :: Bool
-
-T14794c.hs:15:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
+T14794c.hs:10:1: warning: [-Wmissing-signatures (in -Wall)]
+    Top-level binding with no type signature: testUnexported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794d.hs b/testsuite/tests/warnings/should_compile/T14794d.hs
index 8928df75d3..bb9913e6d9 100644
--- a/testsuite/tests/warnings/should_compile/T14794d.hs
+++ b/testsuite/tests/warnings/should_compile/T14794d.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures #-}
+{-# OPTIONS_GHC -Wmissing-pattern-synonym-signatures #-}
 
-module T14794d (test1, pattern Test2, test3, pattern Test4) where
+module T14794d (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures
+-- These should generate warnings:
 
-test3 = True
+pattern TestExported <- True
 
-pattern Test4 <- True
+pattern TestUnexported <- True
 
+-- These should not generate warnings:
 
--- This should not generate warnings with;
--- -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures
+testExported = True
 
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
-
-test7 = True
-
-pattern Test8 <- True
+testUnexported = True
diff --git a/testsuite/tests/warnings/should_compile/T14794d.stderr b/testsuite/tests/warnings/should_compile/T14794d.stderr
index 3388d17316..61177b520e 100644
--- a/testsuite/tests/warnings/should_compile/T14794d.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794d.stderr
@@ -1,6 +1,8 @@
 
-T14794d.hs:9:1: warning: [-Wmissing-exported-signatures]
-    Top-level binding with no type signature: test3 :: Bool
+T14794d.hs:8:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
+    Pattern synonym with no type signature:
+      pattern TestExported :: Bool
 
-T14794d.hs:11:1: warning: [-Wmissing-exported-signatures]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
+T14794d.hs:10:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
+    Pattern synonym with no type signature:
+      pattern TestUnexported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794e.hs b/testsuite/tests/warnings/should_compile/T14794e.hs
index 051cf347d6..b53244de6c 100644
--- a/testsuite/tests/warnings/should_compile/T14794e.hs
+++ b/testsuite/tests/warnings/should_compile/T14794e.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-signatures #-}
+{-# OPTIONS_GHC -Wmissing-exported-pattern-synonym-signatures #-}
 
-module T14794e (test1, pattern Test2, test3, pattern Test4) where
+module T14794e (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-signatures
+-- These should generate warnings:
 
-test3 = True
+pattern TestExported <- True
 
-pattern Test4 <- True
+-- These should not generate warnings:
 
-test7 = True
+testExported = True
 
-pattern Test8 <- True
+testUnexported = True
 
-
--- This should not generate warnings with;
--- -Wmissing-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
+pattern TestUnexported <- True
diff --git a/testsuite/tests/warnings/should_compile/T14794e.stderr b/testsuite/tests/warnings/should_compile/T14794e.stderr
index f0e4ddbc4c..b7c70b6e51 100644
--- a/testsuite/tests/warnings/should_compile/T14794e.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794e.stderr
@@ -1,12 +1,4 @@
 
-T14794e.hs:9:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test3 :: Bool
-
-T14794e.hs:11:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794e.hs:13:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test7 :: Bool
-
-T14794e.hs:15:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
+T14794e.hs:8:1: warning: [-Wmissing-exported-pattern-synonym-signatures]
+    Pattern synonym with no type signature:
+      pattern TestExported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794f.hs b/testsuite/tests/warnings/should_compile/T14794f.hs
index c2cf58f174..2ebb7e0235 100644
--- a/testsuite/tests/warnings/should_compile/T14794f.hs
+++ b/testsuite/tests/warnings/should_compile/T14794f.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-exported-signatures #-}
+{-# OPTIONS_GHC -Wmissing-pattern-synonym-signatures -Wmissing-exported-pattern-synonym-signatures #-}
 
-module T14794f (test1, pattern Test2, test3, pattern Test4) where
+module T14794d (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-exported-signatures
+-- These should generate warnings:
 
-test3 = True
+pattern TestExported <- True
 
+pattern TestUnexported <- True
 
--- This should not generate warnings with;
--- -Wmissing-exported-signatures
+-- These should not generate warnings:
 
-test1 :: Bool
-test1 = True
+testExported = True
 
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-pattern Test4 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
-
-test7 = True
-
-pattern Test8 <- True
+testUnexported = True
diff --git a/testsuite/tests/warnings/should_compile/T14794f.stderr b/testsuite/tests/warnings/should_compile/T14794f.stderr
index b751aad98e..fd138d5911 100644
--- a/testsuite/tests/warnings/should_compile/T14794f.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794f.stderr
@@ -1,3 +1,8 @@
 
-T14794f.hs:9:1: warning: [-Wmissing-exported-signatures]
-    Top-level binding with no type signature: test3 :: Bool
+T14794f.hs:8:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
+    Pattern synonym with no type signature:
+      pattern TestExported :: Bool
+
+T14794f.hs:10:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
+    Pattern synonym with no type signature:
+      pattern TestUnexported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794g.hs b/testsuite/tests/warnings/should_compile/T14794g.hs
deleted file mode 100644
index eec2210203..0000000000
--- a/testsuite/tests/warnings/should_compile/T14794g.hs
+++ /dev/null
@@ -1,31 +0,0 @@
-{-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-pattern-synonym-signatures #-}
-
-module T14794g (test1, pattern Test2, test3, pattern Test4) where
-
--- This should generate warnings with;
--- -Wmissing-pattern-synonym-signatures
-
-pattern Test4 <- True
-
-pattern Test8 <- True
-
-
--- This should not generate warnings with;
--- -Wmissing-pattern-synonym-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test3 = True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
-
-test7 = True
diff --git a/testsuite/tests/warnings/should_compile/T14794g.stderr b/testsuite/tests/warnings/should_compile/T14794g.stderr
deleted file mode 100644
index abd3bf205d..0000000000
--- a/testsuite/tests/warnings/should_compile/T14794g.stderr
+++ /dev/null
@@ -1,6 +0,0 @@
-
-T14794g.hs:9:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794g.hs:11:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
diff --git a/testsuite/tests/warnings/should_compile/all.T b/testsuite/tests/warnings/should_compile/all.T
index a2b82c9661..849ae5edfa 100644
--- a/testsuite/tests/warnings/should_compile/all.T
+++ b/testsuite/tests/warnings/should_compile/all.T
@@ -4,7 +4,6 @@ test('T14794c', normal, compile, [''])
 test('T14794d', normal, compile, [''])
 test('T14794e', normal, compile, [''])
 test('T14794f', normal, compile, [''])
-test('T14794g', normal, compile, [''])
 
 test('T9178', [], multimod_compile, ['T9178', '-Wall'])